| 摘要 |
PURPOSE:To increase maximum controllable current by a method wherein a second gate region, having the impurity density lower than the maximum value of impurity density of a gate region and the same conductive type as the gate region, is provided on the side of the cathode region of the gate region, and the impurity density of the second gate region part, which comes in contact with the cathode region located under the part in the vicinity of the center axis of a rectangular cathode region, is locally increased. CONSTITUTION:An anode region 2 of the conductive type different from other regions, a base region 3, a gate region 4 and a rectangular cathode region 6 are provided successively. A second gate region 4A, having the impurity density lower than the maximum value of the impurity density of the gate region 4 and also having the same conductive type as the gate region, is provided on the side of the cathode region 6 of the gate region 4, and the impurity density of the second gate region 4B, which comes in contact with the cathode region 6 located under the part in the vicinity of the center axis of the rectangular cathode region 6, is made higher. For example, after an anode region 2, a base region 3 and a gate region 4 have been formed, the second gate region 4A is formed by depositing an epitaxial layer having the same conductive type as the gate region 4 and the impurity density lower than the maximum value of impurity density of the gate region 4, and then the second gate high density region 4B is formed by selectively diffusing high density p-type impurities on the center part of the second gate region 4A. |
